Zinc plating processes are in wide-spread commercial use for applying a corrosion resistant, and in some instances, a decorative plating upon a variety of substrates, and more particularly upon ferrous articles composed of iron and steel. A considerable number of additive agents have heretofore been used or proposed for use in zinc electrolytes for improving the brightness and leveling characteristics of the deposit. However, because of environmental and other considerations, increased commercial emphasis has recently been placed on so-called non-cyanide zinc plating solutions of the acid and alkaline types. Brightening and leveling agents employed in such non-cyanide plating solutions in accordance with prior art practice, while effective to produce relatively bright zinc platings, have presented problems in some instances due to the relatively high concentrations required in the aqueous solutions to achieve the desired results. Such aqueous zinc plating solutions have also been categorized as being very selective with respect to the work pieces being processed, thereby requiring the maintenance of an inventory of alternative brightening agents and solutions to accommodate processing of a variety of different work pieces.
The problems and disadvantages associated with noncyanide type zinc plating solutions are overcome in accordance with the present invention by which a zinc electroplating bath is provided incorporating an additive agent which is particularly effective in producing brilliant zinc platings when employed in only relatively small amounts, which further enhances the leveling characteristics of the plating bath, and which also have versatility in plating of a broad range of different articles.